Guild Wars 2

What do you mean? Tyrian or Elonan cloud of bats?

I can think of another game in which you can fly around as a cloud of bats: inFamous Festival of Blood. It’s a cool idea, but I don’t think that it will cause the same reaction you think that it will cause. People will get curious, but they won’t necessarily start throwing their money at Anet.

Previously proposed in https://forum-en.gw2archive.eu/forum/game/gw2/Invisible-Glider/first#post5908079 is something that will give you what you are asking for in a much easier way for the programmers to implement. Plus it will give you (and others) the flexibility to have the wings or not as you prefer, moment to moment. Someone might like having the wings with the transformation, after all